Wood Group

Design Methodology for Modifying a MODU into a FPU Anders M Moe

1st March 2017

• Wood Group Introduction

• Background

• Design Differences MODU vs FPU

• Main Design Changes Required for Converting MODU

• Design Case – A5000E to FPU

• Feasibility Evaluation

Agenda

2

To be recognised as the best

technical services company

to work with, work for and

invest in, with a relentless

focus on excellence.

Our vision

We provide smart technical

solutions which create and sustain

value for our customers.

Our purpose

$5bn revenue

About 30,000 people

40 countries

We are experienced

We are where you need us

6

With around 30,000 people

working in more than 40 countries

we have a strong network of

capability and expertise built over

30 years of successful operations

to help you wherever you need it.

We have a proven track record

7

Lightweight topside design

WORLD LEADER IN

In-house software development

Offshore decommissioning

Hook-up & commissioning

O&G brownfield contractor

Standard designs

Full offshore asset

management

Industry specifications for

flexible pipelines

Deepest TLP, SPAR and

platform

Longest and deepest

pipelines

Largest semi-submersible

Offshore wind

projects assessed

WORLD’S LEADING

PIONEER IN

Over 90 countries

PROJECTS IN 11.4GW

DESIGNED THE

WROTE THE

Semi-submersible units

1977 2014

1978197919801981198219831984198519861987198819891990199119921993199419951996199719981999200020012002200320042005200620072008200920102011201220132014

1986

Nortrym""Ross Rig

1997

C. Kirk Rhein Jr.

1999

Bideford Dolphin 2006

Blackford Dolphin1993

Borgny Dolphin

1980

Treasure Finder""Nordraug

1998

Borgland Dolphin1981

2001

GVA 4000MBingo9000-3

Transocean Searcher

1983

T. Swan

2011

COSLProspector

1977

Nordraug

1984

Sedco Phillips SS""T. Finder"

"Byford Dolphin

2002

Borgholm DolphinEirik Raude

1978

Polymariner2009

COSLPioneerCOSLInnovatorCOSLPromoter

1982

Nortrym""T. Hunter""T. Finder 2013

HYSY982Island Innovator

1996

Byford Dolphin

1995

Drillmar""Borgsten Dolphin

1979

Nortrym

1985

Dyvi Stena""Safe Holmia

2013

Safe Caledonia2000

Leiv Erikson

2014

Safe Scandinavia

More than 35 years experience with semi-submersibles

8

• For FPSOs conversion of tankers typically account for close to 2/3rds

• Conversion economically attractive for FPSOs

• Conversion of MODU (drillships, semis or jack-ups) are rare in the last 15 years

• Industry downturn resulting in a dramatic reduction in fleet utilization for MODUs

• Approx. 70% floater utilization per Q4 2016

• Projects are delayed, postponed or cancelled:

– Focus on increased confidence in reservoir and production profiles

– Large investments postponed if possible

– Early production facilities more interesting to some

• Continued strong focus on reducing CAPEX

– Standardization

– Simplification

Background

DEMAND DAYRATES STACKED RIGS

Market Analysis

Source Clarksons Research and IHS

• Drivers for MODU to FPU semi-submersible

conversion:

– Early production facility

– Minimum processing facility

– Full production facility

• May not be feasible for harsh environment areas

Drivers for Conversion

Differences between MODU and FPU

Parameter MODU FPU

Class/Flag Yes Typically designed to Class requirements.

Leased units often have class and flag

Inspection regime Typical 5 years SPS at quayside or dry-

dock

Typically inspection in lieu of dry docking

regimes

Location Worldwide mobile operations and

design for typ. 20 yrs

Remains at location for the

production/lease time (up to 20 yrs)

Mooring & station

keeping

Pre-laid or self mooring

Thrusters and DP

High spec long term pre-laid mooring and

no DP

Fit to purpose

equipment

Drilling eq. and utilities often integrated

in hull structure. (ship-style)

Topside process and utilities normally not

integrated in the hull. (offshore-style)

Transit and speed Transit speed generally a design

requirement

Transit is not relevant

Operational loads VDL (part of deadweight) is the main

design parameter

Topsides weight, footprint and riser loads

are main design drivers

Major evaluation and changes - hull

Hull

• Check and verification of global structure

• Check fatigue life

• Verify payload limitations and stability

• Assess hydrodynamic characteristics

• Assess mooring system arrangement

• Assess riser interface on hull

• Check major tank capacity

• For major buoyancy upgrades, evaluate installation of transverse pontoons

and removal of bracings

• Establish inspection regime in lieu of typical SPS class renewal

Major evaluation and changes – topsides & utilities

Topsides Utilities

• Introduce new process

topsides

• FPU with drilling capabilities

• Complete layout

redesign

• Typical minimum

processing facility

• FPU without drilling

capabilities

• Removal of drilling

equipment

• Design and installation

of new processing

modules

• Review and upgrade utilities

• Cooling water

• Fire system

• Fuel and lub systems

• Power generation

• HVAC

• Safety systems – F&G and ESD

• LQ and working spaces

Weight distribution

Semi submersible MODU Semi submersible FPU

Example MODU FPU

MODU main particulars

Square Column Width 15.50 m

Number of Columns 4

Pontoon Width 16.50 m

Pontoon Height 10.05 m

Operational Draught 17.50 m

Elevation Underside Deck Box 29.55 m

Overall Width 70.50 m

Overall Length 104.50 m

Deck Box Height 8 m

Deck Area 5 812 m²

Displacement (approx.) 40 800 t

Lightship weight 25 500 t

Variable Deck Load 5 000 t

• Base case is to use the same hull and upgrade/modify where necessary to increase

the topside weight

• Particulars are the same but weight budget is changed:

FPU main particulars

Item Weight VCG

Hull Weight (Including Riser and

Mooring Forces)

20 100 t 11 m

Topsides Dry Weight 10 000 t 44 m

Riser & Mooring Loads 3 000 t 2 m

Fluids & Consumables (ex. Ballast) 4 000 t 17 m

Margin 2 000 t 29 m

Ballast 5 700 t 6 m

Total 44 800 t 19.8 m

Potential hull modifications:

1. Blisters and sponsons

• Offers improved stability and additional topsides payload

• Will influence motion characteristics

• Relatively minor modification

2. Replace bracings with transverse pontoon

• Requires modifications to areas subject to high stresses

• Offers significantly increased topsides payload (order of magnitude 5000 tonnes)

• May be positive with regards to service life compared to bracings

3. Transverse pontoon + blisters and sponsons

• Relatively large modification

• Offers significantly improved stability and additional topsides payload

Potential modifications

Potential modifications

1 2 3

Opportunities

• Upgrade and life extension well known to the industry (I.e. Aker H3 rigs from the 1970s still operating, some as deepwater units)

• Steel replacement/renewal also well known in the industry

× Challenges/threats

• Lifetime extension and fatigue sensitive areas

– Pontoon/bracing configuration

• Payload capacity for integrated production and drilling, and for full production facilities

• Riser interface and hang-off

• Mooring arrangement

• Air gap can limit the operational areas

Technical Feasibility Evaluation

Opportunities

• Lease and operate models

• Reduced CAPEX

– Low hull cost

– High number of laid-up rigs

– Reduced topsides cost?

× Challenges/threats

• Cost of upgrade and limitation to the renewal scope

• Topside facility integration

• Suitable fields

– Infrastructure

– Environmental conditions (e.g. wind and wave loading)

– Reservoir characteristics

Commercial Feasibility

• Drilling market situation is pushing many drilling rigs to be laid-up or scrapped

• This gives availability of reusing relatively modern units for other purposes

• Owners and Investors need to be creative in order to reduce the risk of big financial losses

• Modifying a semi-submersible from drilling to production is technically feasible and could be commercially attractive

Conclusion